1. Field of the Invention
This invention relates to the field of household electrical appliances, e.g., washers, dryers, refrigerators, air conditioners, and the like, and is particularly directed toward providing a means for establishing a support post for a grommet that is normally used in supporting a vibratable platform upon which is mounted the air compressor or motor and the like of such appliances.
2. Description of the Prior Art
Heretofore, grommets used for this purpose have been supported by incorporating a shoulder bolt or screw, i.e., like that shown in FIG. 7 of the drawings. A common problem in the manufacturing of many designs of shoulder bolts is well known in any industry. In other words, the industry recognizes that shoulder bolts cannot readily be constructed in which the thread structure is uniform all the way up to the shoulder. Moreover, many such designs of shoulder bolts inherently have a condition of thread under size adjacent to the shoulder, or the threads are not rolled up to the shoulder. This thread characteristic causes considerable aggravation when depending upon the shoulder bolt to support a grommet which is used in the manner herein described.
It should be pointed out that in certain uses, this problem can readily be overcome by simply shimming the undersize or partial thread area by incorporating a washer or the like. However, this additional cost nullifies the justification for the expensive one piece shoulder bolt. Thus the undersize or partial thread structure is not relied upon for providing support to the bolt and/or shoulder. On the other hand, a serious problem is encountered when these prior type shoulder bolts (or screws) which have self-threading screws and wherein they are adapted to readily engage relatively thin sheet metal structure. This problem simlply stated is: that the poorly formed threads adjacent the shoulder often cause a spinout. In other words, the larger well-formed thread portion of the bolt first establishes a large diameter pattern in the sheet metal for the threads to engage, but when the shoulder bottoms or the threads adjacent the shoulder engage the sheet metal, the undersize or partial thread structure adjacent the shoulder is brought into play. However, these undersize threads cannot properly grip the sheet metal structure. Thus the bolt becomes ineffective. It is well known to those skilled in the art that this problem is very costly since considerable man hours are lost in the assembly process. Additionally, the sheet metal base pan or plate structure oftentimes must be discarded since the thread structure formed in the sheet metal has been stripped thus rendering it useless.
Therefore, it may readily be seen that thread structure immediately adjacent the shoulder of a shoulder bolt is critical to proper seating of the shoulder upon the sheet metal base pan or plate, i.e., undersize or poorly formed threads in this area cause spinout of the bolt and prohibit tightening the shoulder down onto the base pan or plate.